In many communication systems, bundles of optical fibers extend significant distances between two points. In many office buildings, these bundles of fibers terminate in a wiring closet. In a typical wiring closet, there may be hundreds of optical fibers. Upon leaving the wiring closet, these fibers diverge along different paths, extending through ceilings and walls to various other termination points in different parts of the building. In some cases, fibers that begin in a wiring closet extend to neighboring buildings.
In many cases, the fibers appear identical to each other. Accordingly, it is often difficult for maintenance personnel to determine which of the many wires in a closet is the one that extends to a particular location. To address this, difficulty, one typically shines a light through individual fibers and visually inspects the other ends of the fibers.
Occasionally, a few optical fibers will break, or otherwise lose continuity. Proper maintenance of such communication systems typically include identifying broken fibers.
One way to identify broken fibers is to shine a light at a first end and look at a second end to see if a light exits out the other end. However, this procedure is carried out one fiber at a time, and is therefore time consuming.
Another option is to shine a light through the first end of each of several fibers at the same time. However, even if one were to identify a fiber having a dark second end, it would not be possible to easily determine which fiber's first end the dark second end would correspond to.